In spring, trees are some of the first plants to produce pollen and nectar for bees. Food helps bumblebee queens establish colonies, similar to the way that early childhood nutrition is important for people throughout their lives.

On May 21st, 29 students arrived at the Harvard Forest from around the country and the world, to take part in our 2012 Summer Research Program in Ecology. For 11 weeks, these students will live on-site and be mentored on a full-time, independent research project.

For a long time, botanists have known that freeze-thaw cycles in spring determine sap flow in maple trees. Sugar content in the sap also varies from year to year, but less is known about why. One possibility is that plants only have so much sugar to go around, so years when trees make lots of seeds are followed by years with less sugar in the sap.

Scientists at the Harvard Forest are trying to answer a question that is now more than 100 years old: how did the 11 different species of North American pitcher plant evolve? A new paper by Research Fellow Wyatt Oswald, Research Assistant Elaine Doughty, former Bullard Fellows Gidi and Rina Ne'eman, and Senior Ecologist Aaron Ellison, adds new insight to the relationships between these 11 species by showing differences in the shape and size of the plants' pollen.

The researchers working in Senior Ecologist Elizabeth Crone's lab are engaged in a diversity of projects ranging from butterfly population dynamics to sugar maple seed production. Rui Zhang, a post-doctoral fellow who arrived in October, is collaborating with Finnish researcher Anne Jäkäläniemi to investigate how habitat transitions affect populations of Silene tartarica, an endangered riparian plant native to Finland.

Last month, Harvard Forest hosted its first Microbial Ecology Symposium, organized by Harvard Forest collaborator Serita Frey, a UNH biologist. The full day included talks and posters from senior scientists in the Harvard Forest LTER program (Stinson, Frey, Melillo, Ellison, Tang), as well as post-docs, graduate students and undergraduates (including a summer 2011 REU student). Topics included microbial responses to soil temperature, the role of microbes in ecosystem function, and fungal demography and community structure.

Harvard Forest ecologists Elizabeth Crone, Josh Rapp and Keala Cummings recently visited Oulanka National Park in northeastern Finland to study how changes in forest cover and river flow affect forest wildflower populations. Their collaborator, Dr. Anne Jäkäläniemi, a botanist with the Finnish Forest and Park Service, will be in residence at Harvard Forest through the end of October. In addition to her plant research, Anne is writing a series of columns about life in the United States for her local Finland newspaper.